A few months ago a relative picked up a Samsung Galaxy Note 3 (SM-N9006) while in China. The price was low so he didn't think much of it. The phone looks genuine and when it boots up it shows the Samsung logo and all that.

While researching a problem with the preinstalled apps - see my other question here - and looking into rooting it, and/or installing a custom rom, it was made clear that I had to be careful to pick the right rom for the device. It was also pointed out that there are clones of these phones which complicates the problem.

So, my question is, how do I know if I have a genuine Samsung Note 3 or a cheap clone?

Device Info:
Samsung Galaxy Note 3 SM-N9006
Android 4.4.2
Baseband: MT6582
Build: JSS15J.N9006ZCUBMI5